干湿交替诱导水稻根表铁膜形成的基因表达谱分析

Gene Expression Profile Analysis for Alternate Wetting and Drying Induced Formation of Iron Plaque on Root Surface of Rice Seedlings

【目的】干湿交替(AWD)是水稻种植过程中最重要的管理方式,能够提高水稻根系活力、增强抗逆性。研究发现,AWD能明显促进水稻根表铁膜的形成。然而,AWD诱导水稻根表铁膜形成的基因表达谱尚未见报道。【方法】采用砂培试验,研究了长期淹水(CK)、干湿交替(AWD)、长期淹水加Fe2+(CK+Fe)和干湿交替加Fe2+(AWD+Fe)四个处理下水稻根系基因的差异表达谱。【结果】AWD处理与CK处理相比,水稻根系有506个差异表达基因(DEG)上调表达,有687个DEG下调表达;AWD+Fe处理与CK+Fe处理相比,有308个DEG上调表达和179个DEG下调表达;CK+Fe处理与CK处理相比,有728个DEG上调表达和1175个DEG下调表达;AWD+Fe处理与AWD处理相比,有1252个DEG上调表达和1189个DEG下调表达。维恩图分析发现,共计有3822个DEG参与了AWD诱导水稻根表铁膜形成过程。基因功能(GO)分析表明,在生物过程中共有270个DEG参与了氧化还原反应过程,分子功能中共有165个DEG与氧化还原酶功能有关。生物通路富集分析(KEGG)结果表明,细胞器类、信号刺激类、光合作用类、生物合成类和代谢类等生物通路参与了AWD诱导水稻根表铁膜的形成过程。AWD和根表铁膜形成过程发现有38个共享DEG,这些基因的蛋白注释与水稻抗病性、抗旱性、细胞壁和细胞膜、氧化还原、蛋白激酶和转运、新陈代谢过程有关。与CK处理相比,AWD处理诱导了氧化还原反应过程相关的基因达102个,占总DEG数的8.25%。AWD处理促进了水稻根系过氧化物酶、脂肪酸氧化酶和乙醇酸氧化酶等相关基因的上调表达。与CK处理相比,AWD处理提高了水稻根系活力和根表铁膜数量,分别为22.9%和45.7%。实时荧光定量PCR验证结果与转录组分析结果基本一致,其相关系数达到0.90。【结论】综上所述,AWD明显诱导了氧化还原反应过程中的相关基因大量表达,增加了根系氧化力,促进根表铁膜的形成;过氧化物酶、脂肪酸氧化酶和乙醇酸氧化酶等相关的基因可能是AWD诱导水稻根表铁膜形成的重要基因。

【Objective】Alternate wetting and drying(AWD)could enhance root activity and resistance to environmental stresses,which is the most important management in rice cultivation.AWD could induce the formation of iron plaque on root surface of rice seedlings significantly.However,differentially expressed genes(DEG)of rice roots remains unknown in the process of AWD induced formation of iron plaque.【Method】In this study,DEG of rice roots were investigated in response to waterlogging(CK),AWD,CK+Fe,AWD+Fe treatments in sand-culture experiments.【Results】Compared with CK,AWD induced up-regulated expression of506DEG and down-regulated expression of687DEG.Compared with CK+Fe,AWD+Fe induced up-regulated expression of308DEG and down-regulated expression of179DEG.Compared with CK,CK+Fe induced up-regulated expression of728DEG and down-regulated expression of1175DEG.Compared with AWD,AWD+Fe induced up-regulated expression of1252DEG and down-regulated expression of1189DEG.Results from Venn diagram analysis indicated that3822DEG wereinvolved in the process of AWD-induced formation of iron plaque on root surface.Gene Ontology(GO)analysis showedthat a total of270DEG participated in the oxidation-reduction process,and165DEG were related to the functions ofredox enzymes.Kyoto encyclopedia of genes and genomes(KEGG)results indicated that DEG involved in organelleclass,signal stimulus,photosynthesis,metabolism and synthesis etc.participated the regulatory process of AWDinduced formation of iron plaque on root surface.Thirty eight shared genes showed differential expression in process ofboth AWD and the formation of iron plaque.The proteins encoded by these genes were responsible for the resistance todisease,drought,redox,translocation and metabolism of rice.In comparison to CK,AWD induced102DEG in theprocess of oxidation and reduction,which accounted for8.25%of the total.AWD enhanced up-regulated expression ofgenes that were associated with peroxidase,fatty acid oxidase,glycolic oxidase etc.In comparison to CK,AWD raisedroot activity and amount of iron plaque on root surface by22.9%and45.7%,respectively.Results of real-time RT-PCRconfirmed the transcriptional group analysis with the correlation coefficient0.90.【Conclusion】AWD induced expression of many differential genes,enhanced root oxidative capacity,and formed iron plaque on root surface.Peroxidase,fatty acid oxidase and glycolic oxidase might be important genes involved in AWD-induced formation of iron plaque on root surface of rice seedlings.